The Johns Hopkins University is a national and international leader in HIV clinical research. The proposed Johns Hopkins University AIDS Clinical Trials Unit (CTU) will bring together three independently funded HIV clinical research groups that perform (1) adult and (2) pediatric treatment trials, and (3) HIV prevention research. These three groups will form a unified CTU serving three DAIDS clinical research networks at one Clinical Research Site (CRS), The Johns Hopkins Medical Institutions in East Baltimore. The Site will be affiliated with the proposed (1) AIDS Clinical Trials Group (ACTG) Network, (2) International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) Network, (3) HIV Prevention Trials Network (HPTN). We have a long history of substantive contribution to the DAIDS scientific agenda, especially in the areas of prevention and treatment trials, early phase drug development and experimental therapeutics, neurology, hepatitis virus and HIV co-infection, and pediatric, adolescent, and maternal-fetal research. The investigators in this proposed CTU have authored over 1,000 published papers related to HIV infection, >300 of these in the past five years. The same investigators hold 21 HIV-related NIH-funded grants as Principal Investigator or Co-Principal Investigator for over $7,000,000 in annual direct costs. Our existing Adult ACTG Unit ranks first nationally in recruitment of African-Americans and women, many of whom have a history of substance abuse. Data management is rated outstanding, and subject retention is exemplary. The CRS will recruit from affiliated clinics serving more than 30,000 HIV-infected and at-risk persons. This new CTU will bring together a large group of accomplished investigators with a strong history of collaboration, and will allow consolidation of administrative resources for regulatory affairs, data management, outreach, and recruitment. While preserving the successful aspects of our current HIV clinical trials structure, this reorganization will benefit the institution by providing a centralized, shared administrative core, which will allow an economyof scale that has not previously been possible at Johns Hopkins. Above all, the joining together of these three groups will provide access to HIV prevention and treatment research across the age spectrum, from birth to adolescence to adulthood and senescence. This CTU is well-positioned to continue its broad and substantial contributions to national and international HIV clinical research, while also serving its community.